Known is a reversible heat-transfer device [1] which comprises evaporating chambers consisting of a heated portion and a compensation cavity, each equipped with an internally-accommodated a capillary porous packing having a central blind channel and a system of vapor-removal channels on thermal contact surfaces that communicate with a vapor collector.
The drawback of such design is the fact that the possibilities for reducing the diameter of the evaporating chamber are considerably limited as the thickness of the layer of the packing separating its absorbing and evaporating surfaces should be sufficiently large to prevent vapor penetration and decrease parasitic heat flows into the compensation cavity. However, when the evaporating chamber diameter is reduced to 4-8 mm, the packing layer thickness decreases, such that it can no longer exhibit a sufficiently high thermal resistance to the heat flow that penetrates into the compensation cavity. As a result, the temperature and pressure difference between the evaporating and the absorbing surfaces of a packing becomes insufficient for providing circulation of the heat-transfer medium in a device.
Known an evaporating chamber of a loop heat pipe [2] which consists of a heated portion and a compensation cavity, and comprises a body with side and a end-face walls, an internally-accommodated a capillary porous packing that is adjacent to the inner lateral surface of the chamber having a central blind channel, whose length is limited by length of the compensation cavity, and a system of vapor-removal grooves on the inner thermal contact surface in the heated portion of the chamber.
Such evaporating chamber may have a sufficiently small diameter meeting the requirements of miniaturization, which is achieved by absence of a central channel in the packing, wich channel would extend deep into the heated portion. However, the conducted tests have shown that the same circumstance brings about drawbacks of such design, which are a low maximum heat load due to an high hydraulic pressure of a packing.
In terms of the set of essential features and the attained result, the art most pertinent to the invention is an evaporating chamber [3] comprising a body which includes a side and end-face walls and a capillary porous packing positioned therein and having vapor-removal channels tied together by a vapor collector and located on a part of the packing perimeter at the heat-supply side, and having an asymmetrical longitudinal opening shifted in the direction opposite to the heat-supply side, the end-faces of the vapor-removal channels on both sides being blind.
Such arrangement for replenishing the evaporating chamber with a heat-transfer medium is more efficient as it makes it possible to considerably reduce the pressure loss when a heat-transfer medium is filtered a capillary porous packing, and an increased thickness of the locking wall achieved by shifting the asymmetrical longitudinal opening in the direction opposite to heat-supply side decreases a value of parasitic heat flows penetrating into the compensation cavity.
A drawback of such design is a reduced heat load at a given operating temperature. This circumstance is caused by the fact that the packing has a through longitudinal opening, whose both ends communicate with the compensation cavity. Parasitic heat leakages into the compensation cavity thereby increase accordingly, as the packing has two locking layers disposed on at side of its both end-faces. Besides, the presence of two locking layers increases length of the evaporating chamber. Another drawback of such evaporating chamber is the fact that the vapor collector, to which the vapor line of a loop heat pipe is connected, is disposed on the chamber side surface, which circumstance also increases dimensions of, and makes the device arrangement on a cooled object more difficult.